The aside Juliet speaks in Act 3, Scene 5 is most definitely emotionally revealing, creating the effect of revealing a great many things about Juliet's character. One reason why the aside is so important is because in a scene not too long ago we witness Juliet crumble and nearly decide she hates Romeo. She had to rationalize herself into being able to trust and respect him again. We see Juliet's emotional turmoil and her budding feelings of hatred for and distrust in Romeo in her lines:

Was ever book containing such vile matterSo fairly bound? O, that deceit should dwellIn such a gorgeous place! (III.ii.86-88)

In other words, Juliet is saying that due to Romeo's handsome exterior she believed him to be virtuous and trustworthy; however, now that he has killed her cousin, she is shocked to feel that someone that looks like him could actually be so "vile" and deceptive. Regardless, once Nurse starts speaking ill of Romeo as well, Juliet has an awakening and realizes she should not think poorly of her husband. Instead, it's her duty as his wife to continue trusting and respecting Romeo and even concludes that he must have killed Tybalt out of self-defense. Therefore, Juliet's aside later in Scene 5 of Act 3 shows us that she is remaining steadfast in her conviction to continue to trust Romeo, which we see in her line, "Villain and he be many miles asunder," meaning that the term "villain" cannot justly be applied to describe Romeo's character (III.v.84). The second line in her aside showing us that she is remaining firm in her decision to trust and honor her husband is the line asking God for Romeo's forgiveness and saying that she has already forgiven Romeo "with all [her] heart" (85). Hence one reason why this aside is so important is that it shows us just how much Juliet's character has developed and how she has matured into a woman who now understands that love comes with many hardships.

Another reason why the aside is so important is that it reveals her emotions when she says, "And yet no man like he doth grieve my heart" (86). This line can be interpreted a couple of different ways, and both interpretations would be equally true and equally revealing. One reason why she may be saying that "he doth grieve [her] heart" is that he is grieving her heart because he must now be separated from her due to his banishment. The second reason why she may be saying the line is that he has grieved her heart by killing Tybalt. Both are equally true, and both reveal just how much she is struggling emotionally due the fact that Romeo has killed Tybalt.

Therefore, the effect of the aside is to reveal a great many things about the emotional turmoil Juliet is going through due to Romeo's actions and his banishment.